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fizz

fizz is a skill for Claude Code, Codex from ccashwell/evm-cortex. It costs 60 tokens per session (10,931 once invoked), scanned A, a copy of fizz, MIT.

A generator for Solidity fuzz-testing suites that check whether contract rules remain true across many inputs and transaction sequences. It creates the harness, metadata, and runtime files for Echidna and Medusa, with Foundry used for compilation and smoke tests.

In plain words
What is it for?
Use it to generate stateful fuzzing harnesses and invariant suites for Foundry or Hardhat Solidity projects.
Why use it?
It removes much of the setup needed to test smart contracts for unexpected state changes and invariant violations.

Skill for Claude CodeCodex

Written for no agent in particular: nothing here depends on one. Also seen: mentions subagents; names the AskUserQuestion tool; mentions Claude Code.

not rated 131repo 17d ago A scan 60 tokens copy · 98% MIT

Good fit Use it to generate stateful fuzzing harnesses and invariant suites for Foundry or Hardhat Solidity projects.

Compare 6 skills from other repositories ↓
Install with agentmods
npx agentmods add skills/ccashwell/evm-cortex/fizz
View source ↗ ccashwell/evm-cortex
Install

Getting it into your agent

One page per mod, every tool's command on it. A separate URL per tool would split the same page into five that compete with each other.

Any agent
npx skills add ccashwell/evm-cortex --skill fizz
Clone the repo
git clone --depth 1 https://github.com/ccashwell/evm-cortex

Made for: Claude Code, Codex.

Wrote this? Show the measurements

A badge with what this costs and how it scanned, read live from this page, so it follows the numbers instead of freezing them. Markdown for a README, HTML for a documentation site or a project page.

agentmods badge for fizz

README.md
[![agentmods](https://agentmods.dev/badge/skills/ccashwell/evm-cortex/fizz/github.svg)](https://agentmods.dev/skills/ccashwell/evm-cortex/fizz)
Your own site
<a href="https://agentmods.dev/skills/ccashwell/evm-cortex/fizz"><img src="https://agentmods.dev/badge/skills/ccashwell/evm-cortex/fizz/github.svg" alt="Measured on agentmods" height="20"></a>

Or the 80×15 button, for a site that already has a row of RSS and ATOM ones. Only the verdict fits; the numbers stay here.

agentmods 80×15 button for fizz

Your own site · 80×15
<a href="https://agentmods.dev/skills/ccashwell/evm-cortex/fizz"><img src="https://agentmods.dev/badge/skills/ccashwell/evm-cortex/fizz.svg" alt="Reviewed on agentmods" width="80" height="20"></a>
Per session 60 Skills are progressive disclosure: only the name and description are preloaded; the body loads when the skill is used.
When invoked 10,931 The whole file, excluding the scripts and references it only reads on demand.
Security scan A 1 finding. A grade says what 26 rules found in the file — not that it is safe.
Origin 98% copy Near-identical to another mod in the catalogue.
Token cost

What it costs to keep this loaded

Counted locally with the o200k_base tokenizer, which is exact for GPT models; Claude uses its own tokenizer and its counts differ. Treat this as one consistent yardstick across the catalogue rather than a bill. Prices are per million input tokens.

ModelPer sessionOnce invoked
Fable 5.1 $0.00060 $0.10931
Opus 5.5 $0.00024 $0.04372
Sonnet 5.5 $0.00012 $0.02186
Haiku 4.5 $0.00006 $0.01093

Measured 1mo ago against content hash 50e92f39387d, method: parsed. Prices are Anthropic first-party input rates as of 2026-10-07, from the pricing page.

Security

Grade A, and why

fizz scanned grade A with 1 finding against 26 rules in 11 categories — prompt injection, anti-refusal, data exfiltration, privilege escalation, supply chain, agent snooping, system-prompt leakage, SSRF and excessive agency — measured 1mo ago.

The scan reads SKILL.md. This mod also ships 11 executable files (scripts/ensure_foundry.sh, scripts/estimate_cost.js, scripts/extract_abis.js, …), listed below but not scanned — reading those needs a real analyzer, not pattern matching.

A static scan of the body, not an audit. Every finding is printed with the line that produced it so you can judge whether it matters here. A mod is markdown that instructs an agent; that is exactly why what it instructs is worth reading.

Makes network callslowCapability

Not a fault in itself. Listed so you know the mod talks to something, and to what.

curl -sf https://raw.githubusercontent.com/pashov/skills/main/fizz/VERSION
Origin

This is a copy

98% identical to fizz — 28 lines differ, which has more behind it and is treated as the original. This page carries a canonical link to it rather than competing with it.

skills/fizz/SKILL.md · 605 lines

How it starts

The opening of the file, as written. The whole thing — 605 lines — stays where its author put it; the contents beside it link to each section on GitHub.

Fizz

Generate a stateful Solidity fuzz suite under {SUITE_DIR} (default: test/fizz/), with metadata and fuzzer runtime files under {META_DIR} (default: fizz_data/).

Use Echidna and Medusa for invariant campaigns. Use Foundry for compilation, smoke testing, and quick debugging.

Vendored from the Pashov Audit Group's open-source approach (github.com/pashov/skills), skill fizz, VERSION 1 (see the VERSION file alongside this one). The scripts/, templates/, references/, and agents/ directories are upstream code carried over intact; the only local adaptations are the x-ray acquisition path in Step 3 (EVM Cortex ships the methodology as the xray-pre-audit skill) and the companion-skill locations noted below. Check for a newer upstream revision before relying on this:

curl -sf https://raw.githubusercontent.com/pashov/skills/main/fizz/VERSION

Relationship to other EVM Cortex skills

Skill Relationship
xray-pre-audit Produces the x-ray/x-ray.md protocol understanding that Step 3 consumes. Run it first — the fallback Protocol Analyzer is strictly worse input for invariant discovery.
fizz-sync Re-use entry point. After source changes, run it instead of regenerating the suite.
fizz-convert Turns plain-English properties added to PROPERTIES.md into Solidity assertions.
invariant-testing, fuzzing-patterns Reference material for hand-writing or reviewing properties and handlers outside this pipeline.
pashov-audit-pipeline Complementary, not overlapping — that pipeline reasons about attack paths, this one drives a fuzzer at the state space. A violated SHOULD-HOLD property here is strong input to a finding there.

Workflow Rules

  • Follow the steps in order. Do not skip forward if a required artifact for the current step does not exist yet.
  • If a step fails, stop there and report the blocker.
  • If tooling is missing, say exactly what was attempted and what is missing.
  • Keep the generated Solidity suite isolated under test/fizz/ and the metadata/runtime files under fizz_data/ unless the user explicitly asks for different paths.
  • Reuse existing project setup and test logic whenever possible; do not invent a deployment flow if the repo already has one.

Read the full file on GitHub · 605 lines

Files

What ships with it

47 files beside SKILL.md in the same directory: the scripts, references and assets a skill reads on demand. Not counted in the per-session cost; read them before you install if any of them is executable.

Changes

What this file has done since we first saw it

Hashed on every crawl. A supply-chain change to an agent config is a question of when, not whether, so the history is kept rather than the latest state alone.

  1. 1mo ago First seen · 605 lines · 60 tokens per session scan A 50e92f39387d

Subscribe to this mod's changes

fizz is a skill published in the GitHub repository ccashwell/evm-cortex (131 stars, last pushed 17d ago), licensed MIT. It adds 60 tokens to every session and 10,931 once invoked, about $0.0002 per session on Opus 5.5. A static security scan graded it A with 1 finding (makes network calls). It is 98% identical to fizz, differing in 28 lines, and is treated as a copy.

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